Oral care compositions present particular challenges in preventing microbial contamination. Arginine and other basic amino acids have been proposed for use in oral care and are believed to have significant benefits in combating cavity formation and tooth sensitivity.
Commercially available arginine-based toothpaste for example, contains arginine bicarbonate and precipitated calcium carbonate, but not fluoride. The carbonate ion is believed to have cariostatic properties, and the calcium is believed to form in complex with arginine to provide a protective effect.
However, the formulation of certain oral care compositions presents special challenges. For example, oral care compositions comprising arginine or basic amino acids may have a basic pH, increasing potential for microbial contamination compared to acidic formulations. Moreover, not all preservatives are active at higher pH. Some preservatives negatively affect the taste or aesthetics of the product. While certain preservatives, such as ethanol or parabens, are known to be effective at a range of pHs, these preservatives are not suitable for all products or all markets.
Accordingly, there is a need for improved preservative agents for use in oral compositions comprising basic amino acids.